The Sitemap XML protocol is also extended to provide a way of listing multiple Sitemaps in a 'Sitemap index' file. The maximum Sitemap size of 50 MiB or 50,000 URLs means this is necessary for large sites. An example of Sitemap index referencing one separate sitemap follows.
Cultural or artificial eutrophication occurs when human activity introduces increased amounts of these nutrients, which speed up plant growth and eventually choke the lake of all of its animal life.n nature, eutrophication is a common phenomenon in freshwater ecosystems and is really a part of the normal aging process of many lakes and ponds. Some never experience it because of a lack of warmth and light, but many do.
Eutrophication arises from the oversupply of nutrients, which induces explosive growth of plants and algae which, when such organisms die, consume the oxygen in the body of water, thereby creating the state of hypoxia. According to Ullmann's Encyclopedia, the primary limiting factor for eutrophication is phosphate..The availability of phosphorus generally promotes excessive plant growth and decay, favouring simple algae and plankton over other more complicated plants, and causes a severe reduction in water quality.ultural eutrophication also occurs when excessive fertilizers run into lakes and rivers. This encourages the growth of algae (algal bloom) and other aquatic plants. Following this, overcrowding occurs and plants compete for sunlight, space and oxygen.